Lucario LTR 80

If this Pokémon is your Active Pokémon and is damaged by an opponent's attack (even if this Pokémon is Knocked Out), put 2 damage counters on the Attacking Pokémon.

Does 20 damage to 1 of your opponent's Benched Pokémon. (Don't apply Weakness and Resistance for Benched Pokémon.)